Over recent years continuous improvements in our healthcare have resulted in dramatic demographic changes, e.g. an increase in the average age of the population. These demographic changes are causing an increase in the prevalence of diseases associated with aging. Many of these diseases arise from the loss or dysfunction of specific cell types in the human body, leading to permanently damaged tissues and organs.
A relatively new field of medicine—since the early 1990s—is the field of Regenerative Medicine. Regenerative Medicine is the process of creating living and functional tissues to repair, replace, or restore tissue or organ structure and function lost due to age, disease, damage, or congenital defects. This field of medicine uses new methods including (stem) cell therapy, development of medical devices and tissue engineering.
The technique of tissue engineering consists of constructing substitutes (e.g. biological substitutes) for diseased tissues. Tissue engineering makes use of natural or polymeric scaffolds that provide mechanical support and promote the re-growth of cells lost due to trauma or disease. A scaffold is a temporary structure used to support material (e.g. tissue) during the recovery thereof.
A tissue engineering scaffold is usually implanted in vivo at the site in question and is slowly populated with cells, either by capturing progenitor cells form circulation or by in-growth of cells from neighbouring, healthy, tissue. Alternatively, the scaffolds can be pre-seeded in vitro with the appropriate cells prior to implantation. In most cases, as the formation and the remodelling of the newly formed tissue proceeds, degradation of the scaffold should slowly and steadily take place, leaving only new healthy tissue behind. With degradation is meant the breakdown of the material into smaller parts, e.g. chemical compounds and/or elements that can be eliminated from the body by means of excretion in urine for example. The degradation can be effected by the conditions in the body, such as the presence of water combined with the use of water-degradable material for the scaffold.
In order to monitor how fast the in vivo degradation of the scaffolds proceeds and in order to judge the ultimate success of the tissue engineering procedure, it is essential to develop scaffolding materials that are visible in relevant clinical imaging techniques, such as computed tomography (CT), magnetic resonance imaging (MRI) and/or diagnostic sonography (or ultrasonography) using ultrasound for imaging purposes, for example.
Since both natural and polymeric scaffolds themselves deliver little or no contrast compared to the surrounding tissues—because they are closely related in structure and material—imaging labels are required as contrast agents within the scaffolds. An imaging label is an identifying marker that may be attached to a material to be identified.
It is an aim of the present invention to provide an imaging label or contrast agent that can be used in solid objects, for instance in scaffolds.
It is a further aim of the present invention to provide a solid object, for instance a scaffold including an imaging component or contrast agent that can be visualized in clinical imaging techniques.
One or more of the above aims have been reached by the present invention.
The inventors have surprisingly found that it is possible to use 19F MRI for solid objects using fluorinated polymers as contrast agents or imaging labels.